Vent system for deferred action battery



Dec. 9, 1969 T. H. PURCELL, R 3, 83 0 VENT SYSTEM POR DEFERRED ACTION BATTERY Filed May 24, 1967 ELECTROLYTE diaphragln 17, pp0site the vent opening l In this nlan ner, the electr01yte and gas in the vent chamber can escape through the vent opening 1G and vent lille 18 When the metal diaphragm 17 iS Sumciently corfoded by the electrolyte that the internal battery pressurre can burst the Inetal diaphragn The vent chaInber 15 has angeS l and 20 and the vent line haS Hanges zl and zz' The vent line 18 is attached to the vent chamber 15 by means of bolts 23 and 24 Vvhich are 0Siti0ned in the Hanges and Which also holds the metal diaphragm in place It Should be noted that the vent opening l is preferab]y located in the 10vver corner of the vent chan1ber 15 di ametricauy opposite t0 the electr01yte inlet port 14 in order to illsure that the electrolyte Will contact the metal diaphragn1 17] In his manner, the battery can be dis- 10cated fron1 its n0nal p0sition S0 that the side 25 0f the vent chalnber ls becomes the bottom of the vent chamber, and the battery electrolyte Will Still contact the metal diaphragm 17.

The follovving eanples illustrate the eectiveneSS and the reliability Of a delay action battery vent System in ac cordance with this invenion;

Example I Twenty deferred action battery systems were tested to determine the time elapsed between initiation of activation and venting of the battery. A sheet 0 aluminum foil having a thickness of 0.0005 inch was used as the metal diaphragm Which had a burst pressure (non-corroded of 12S .S.i. The battery activation ressure, ie. the equilib rin pressure within the battery after activation, vvas 50 .S'i.

For the 20 vent SysteIns vvhich vvere tested, the average time between initiation of activation and venting was 4-97 nlinutes The Shortest time vvaS 3.25 minutes and the10ngeSt time was 7'2S minutes Example II Twenty deferred action battery vent systems having the Same design as the vent systems in Example I Were tested to determine the tiIne elapsed between initiati011 0f actva tion and venting Of the battery 11Sing a dieTent activation pressure' Again, a sheet of aluminum foil having a thick ness of o.000j inch vvas used aS the 1etal diaphragn Which had a burst pressure 0f l2 p.s i In this teSt, the battery activation pressure was reduced to 2j p'si 1 0I' the 20 vent syste[ns vvhich K'ere tested the average tinle between initiation of activation and venting was 7 84 T1inlltes The Shortest time vvas 6.S Ininlltes and the longest tine was 9.7 minutes IIaving conlp1etely descfibed this invention, What is claimed iS:

1. In a deferred action battery having a plurality of cells containing a positive electrode, a negative electrode, a Separator between Said 0Sitive and negative electrodes, and activated by a battey electrolyte S0lution which asses through a manifold connected to each cell, the improvement Which comprises a delay action battery vent System comprising a vent chamber attached to Said manifold by means of an electrolyte entry port Whereby a p0rtion ()f the activating elect10lyte can pass into said vent cham ber, a vent opening 10cated in the bottom of said vent chamber, a Inetal dia hragm covering Said vent opening and located between the vent opening and a vent line which is attached to said vent chamber and Said metal diaphragm being of a metal which reactS Tapidly with and is corroded by the battery electrolyte s0ution.

2. A battery in accordance vvith clair1 1 I vvhich the vent opening is 10cated in the lower comer of the vent chamber diametrically 0Pp0site to the electr0lyte entry port 3. A battery in accordance K'ih claim 1 in vvhich the battery elect0lyte iS an alka]ine solution and the nletal diaphragm is aluminum.

leerences cited UNITED STATES PATENTS 2,829,187 4/19j8 McDonald 136llz xR z,872,499 2/19S9 ROW1S et al 136l8l xR 2,886,6Zl 5/19j9 Hinman l36l62 xR vVINSTON A DOUGLAS, Primar Examiner D. L. VVALTON, Assistant Examiner 

